Color and other multi-channel images can be printed using ink jet printers, multicolor transferable toner printers, heat sensitive coated paper printers, thermal dye transfer printers, and other types of printers. Many mass-market retail establishments have user-friendly kiosks at which shoppers make color prints. Because the kiosks use large amounts of paper, the images can be printed on a continuous web of paper, often supplied in roll form and fed from a feed roll to the printhead that applies the image to the receiver. The images are later separated from each other and from the web by a suitable cutter or knife.
It is desirable when roll-feeding to pull the web past the printhead. This provides positive control of the web as it passes the printhead. In various schemes, the printhead forms part of the pulling apparatus, as in U.S. Pat. No. 5,441,353 to Kim. In other schemes, a separate pulling mechanism beyond the printhead is used, as in U.S. Pat. No. 5,021,804 to Nozawa et al. However, printing technologies such as inkjet printing use non-contact printheads, so the printhead cannot form part of the pulling apparatus. Moreover, using a pulling mechanism downstream of the printhead results in the receiver between the printhead and the pulling mechanism being unprinted and discarded, increasing waste and print cost.
Other schemes push the web past the printhead. Examples of such schemes are JP Publication No. H05-147284 (1993) by Kikumura et al. and JP Publication No. 2004-217342 by Iemura et al. However, these schemes do not provide positive control of the receiver until it engages a pulling member sometime after printing begins. This can result in variations in the spacing between the receiver and a non-contact printhead in the leading portion of the image, changing image attributes. These changes can produce a visibly-objectionable difference between the portion of the image pushed past the printhead and the portion pulled past. Pushing the web past the printhead over its entire length exacerbates these problems and can lead to receiver buckle, possibly contacting a non-contact printhead and damaging it (a “head strike”).
There is a continuing need, therefore, for a way of printing images on a continuous web with reduced waste of paper while maintaining consistent image quality.